1. Field of the Invention
This invention relates to an electromagnetic shield for conductors and more particularly to a shield that is particularly useful in shielding a splice in shielded conductors.
2. Description of the Prior Art
Because signal carrying conductors can generate electromagnetic interference (EMI) and because EMI external to a conductor can adversely affect the quality of signals on the conductor, it is known to provide an electromagnetic shield that completely surrounds the circuit conductor and is grounded at one or more points. Typical materials employed for shielding include a fine mesh woven from small diameter conductors and rigid metallic conduit. So long as the integrity of the mesh is maintained, it affords good shielding and possesses a degree of flexibility sufficient to permit conductors to be installed in virtually any desired location.
There are certain environments in which the woven mesh shielding does not afford a complete solution to EMI problems. For example, in certain inexpensive consumer equipment, the cost of woven shielding is not justified. In other cases, where shielded conductors must be spliced, either the mating ends at the splice must be fitted with connectors, which are both expensive and require substantial time to install, or the effectiveness of the shielding will be impaired.
U.S. Pat. No. 3,576,387 discloses a heat shrinkable electromagnetic shield for electrical conductors in which there is a heat shrinkable outer tube on the interior of which is a plastic layer in which conductive metallic particles are embedded. Although the structure described in the cited patent affords EMI shielding superior to a bare wire, the degree of shielding afforded is much less than that obtained with a conductive mesh or metal conduit.